IF YOU WOULD LIKE TO GET AN ACCOUNT, please write an
email to Administrator. User accounts are meant only to access repo
and report issues and/or generate pull requests.
This is a purpose-specific Git hosting for
BaseALT
projects. Thank you for your understanding!
Только зарегистрированные пользователи имеют доступ к сервису!
Для получения аккаунта, обратитесь к администратору.
Currently lvm2app properties have the following structure:
typedef struct lvm_property_value {
uint32_t is_settable:1;
uint32_t is_string:1;
uint32_t is_integer:1;
uint32_t is_valid:1;
uint32_t padding:28;
union {
const char *string;
uint64_t integer;
} value;
} lvm_property_value_t;
which assumes that numerical values were in the range of 0 to 2**64-1. However,
some of the properties were 'signed', like LV major/minor numbers and some
reserved values for properties that represent percentages. Thus when the
values were retrieved they were in two's complement notation. So for a -1
major number the API user would get a value of 18446744073709551615. The
API user could cast the returned value to an int64_t to handle this, but that
requires the API developer to look at the source code and determine when it
should be done.
This change modifies the return property structure to:
typedef struct lvm_property_value {
uint32_t is_settable:1;
uint32_t is_string:1;
uint32_t is_integer:1;
uint32_t is_valid:1;
uint32_t is_signed:1;
uint32_t padding:27;
union {
const char *string;
uint64_t integer;
int64_t signed_integer;
} value;
} lvm_property_value_t;
With this addition the API user can interrogate that the value is numerical,
(is_integer = 1) and subsequently check if it's signed (is_signed = 1) too.
If signed, then the API developer should use the union's signed_integer to
avoid casting.
This change maintains backwards compatibility as the structure size remains
unchanged and integer value remains unchanged. Only the additional bit
taken from the pad is utilized.
Bugzilla reference:
https://bugzilla.redhat.com/show_bug.cgi?id=838257
Signed-off-by: Tony Asleson <tasleson@redhat.com>
Show full chain of ancestors and descendants for snapshots
(both thick and thin - in case of thick, the "ancestor" field
is actually equal to "origin" field as snapshots can't be
chained for thick snapshots).
These fields display current state as it is, they do not
display any history! If the snapshot chain is broken in
the middle, we don't report the historical origin (this
is going to be a part of another patch and a different
set of fields or just a switch for existing fields to
show ancestors and descendants with history included).
For example:
(origin --> snapshot)
lvol1 --> lvol2 --> lvol3 --> lvol4
\
--> lvol5 --> lvol6 --> lvol7 --> lvol8
$ lvs -o name,pool_lv,origin,ancestors,descendants vg
LV Pool Origin Ancestors Descendants
lvol1 pool lvol2,lvol3,lvol4,lvol5,lvol6,lvol7,lvol8
lvol2 pool lvol1 lvol1 lvol3,lvol4,lvol5,lvol6,lvol7,lvol8
lvol3 pool lvol2 lvol2,lvol1 lvol4
lvol4 pool lvol3 lvol3,lvol2,lvol1
lvol5 pool lvol2 lvol2,lvol1 lvol6,lvol7,lvol8
lvol6 pool lvol5 lvol5,lvol2,lvol1 lvol7,lvol8
lvol7 pool lvol6 lvol6,lvol5,lvol2,lvol1 lvol8
lvol8 pool lvol7 lvol7,lvol6,lvol5,lvol2,lvol1
Move the lvm1 sys ID into vg->lvm1_system_id and reenable the #if 0
LVM1 code. Still display the new-style system ID in the same
reporting field, though, as only one can be set.
Add a format feature flag FMT_SYSTEM_ON_PVS for LVM1 and disallow
access to LVM1 VGs if a new-style system ID has been set.
Treat the new vg->system_id as const.
This makes a difference when using selection criteria based on
these fields - if those fields are defined as DM_REPORT_FIELD_TYPE_SIZE
(in contrast to DM_REPORT_FIELD_TYPE_NUMBER), units are also
recognize in selection clause.
For example:
$ lvs -o+seg_start vg1/lv2
LV VG Attr LSize Start
lv2 vg1 -wi-a----- 12.00m 0
lv2 vg1 -wi-a----- 12.00m 8.00m
Before this patch:
$ lvs -o+seg_start --select 'seg_start=8m'
Found size unit specifier but numeric value expected for selection field seg_start.
Selection syntax error at 'seg_start=8m'.
Use 'help' for selection to get more help.
With this patch applied:
$lvs -o+seg_start --select 'seg_start=8m'
LV VG Attr LSize Start
lv2 vg1 -wi-a----- 12.00m 8.00m
(the same applies for ba_start and vg_free fields)
Rename original lv_error_when_full field to lv_when_full and also
convert it from binary field to string field displaying three
possible values: "error", "queueu" or "" (blank for undefined).
$ lvs vg/pool vg/pool1 vg/linear_lv -o+lv_when_full
LV VG Attr LSize Data% Meta% WhenFull
linear_lv vg -wi-a----- 4.00m
pool vg twi-aotz-- 4.00m 0.00 0.98 queue
pool1 vg twi-a-tz-- 4.00m 0.00 0.88 error
For -S|--select these synonyms are recognized:
"error" -> "error when full", "error if no space"
"queue" -> "queue when full", "queue if no space"
"" -> "undefined"
Add separate LVSINFOSTATUS field type for fields which display both
dm info-like and dm status-like information.
The internal interface is there with the introduction of LVSSTATUS
field type which can cope with the combination of LVSSTATUS
and LVSINFO field types (several fields).
However, till now, we considered that *single* field can display
either LVSINFO or LVSSTATUS, but not both at the same time.
Till now, we haven't had single field which needs both - hence
add LVSINFOSTATUS field type for such fields as we currently
need this for the lv_attr field which requires combination of
info and status.
This patch just adds interface for an ability to register such fields
(the code that copes with this is already in).
Recently the single 'status' code has been used for number of cache
features.
Extend the API a little bit to allow usage also for lv_attr_dup.
As the function itself is used in lvm2api - add a new function:
lv_attr_dup_with_info_and_seg_status() that is able to use
grabbed info & status information.
report_init() is now using directly passed lvdm struct pointer
which holds the infomation whether lv_info() was correctly obtained or
there was some error when trying to read it.
Move 'healt' attribute to status.
TODO convert raid function to use the already known status.
Support error_if_no_space feature for thin pools.
Report more info about thinpool status:
(out_of_data (D), metadata_read_only (M), failed (F) also as health
attribute.)
The cache mode of a new cache pool is always explicitly
included in the vg metadata. If a cache mode is not
specified on the command line, the cache mode is taken
from lvm.conf allocation/cache_pool_cachemode, which
defaults to "writethrough".
The cache mode can be displayed with lvs -o+cachemode.
The 'lv_type' field name was a bit misleading. Better one is 'lv_role'
since this fields describes what's the actual use of the LV currently -
its 'role'.
The lv_layout and lv_type fields together help with LV identification.
We can do basic identification using the lv_attr field which provides
very condensed view. In contrast to that, the new lv_layout and lv_type
fields provide more detialed information on exact layout and type used
for LVs.
For top-level LVs which are pure types not combined with any
other LV types, the lv_layout value is equal to lv_type value.
For non-top-level LVs which may be combined with other types,
the lv_layout describes the underlying layout used, while the
lv_type describes the use/type/usage of the LV.
These two new fields are both string lists so selection (-S/--select)
criteria can be defined using the list operators easily:
[] for strict matching
{} for subset matching.
For example, let's consider this:
$ lvs -a -o name,vg_name,lv_attr,layout,type
LV VG Attr Layout Type
[lvol1_pmspare] vg ewi------- linear metadata,pool,spare
pool vg twi-a-tz-- pool,thin pool,thin
[pool_tdata] vg rwi-aor--- level10,raid data,pool,thin
[pool_tdata_rimage_0] vg iwi-aor--- linear image,raid
[pool_tdata_rimage_1] vg iwi-aor--- linear image,raid
[pool_tdata_rimage_2] vg iwi-aor--- linear image,raid
[pool_tdata_rimage_3] vg iwi-aor--- linear image,raid
[pool_tdata_rmeta_0] vg ewi-aor--- linear metadata,raid
[pool_tdata_rmeta_1] vg ewi-aor--- linear metadata,raid
[pool_tdata_rmeta_2] vg ewi-aor--- linear metadata,raid
[pool_tdata_rmeta_3] vg ewi-aor--- linear metadata,raid
[pool_tmeta] vg ewi-aor--- level1,raid metadata,pool,thin
[pool_tmeta_rimage_0] vg iwi-aor--- linear image,raid
[pool_tmeta_rimage_1] vg iwi-aor--- linear image,raid
[pool_tmeta_rmeta_0] vg ewi-aor--- linear metadata,raid
[pool_tmeta_rmeta_1] vg ewi-aor--- linear metadata,raid
thin_snap1 vg Vwi---tz-k thin snapshot,thin
thin_snap2 vg Vwi---tz-k thin snapshot,thin
thin_vol1 vg Vwi-a-tz-- thin thin
thin_vol2 vg Vwi-a-tz-- thin multiple,origin,thin
Which is a situation with thin pool, thin volumes and thin snapshots.
We can see internal 'pool_tdata' volume that makes up thin pool has
actually a level10 raid layout and the internal 'pool_tmeta' has
level1 raid layout. Also, we can see that 'thin_snap1' and 'thin_snap2'
are both thin snapshots while 'thin_vol1' is thin origin (having
multiple snapshots).
Such reporting scheme provides much better base for selection criteria
in addition to providing more detailed information, for example:
$ lvs -a -o name,vg_name,lv_attr,layout,type -S 'type=metadata'
LV VG Attr Layout Type
[lvol1_pmspare] vg ewi------- linear metadata,pool,spare
[pool_tdata_rmeta_0] vg ewi-aor--- linear metadata,raid
[pool_tdata_rmeta_1] vg ewi-aor--- linear metadata,raid
[pool_tdata_rmeta_2] vg ewi-aor--- linear metadata,raid
[pool_tdata_rmeta_3] vg ewi-aor--- linear metadata,raid
[pool_tmeta] vg ewi-aor--- level1,raid metadata,pool,thin
[pool_tmeta_rmeta_0] vg ewi-aor--- linear metadata,raid
[pool_tmeta_rmeta_1] vg ewi-aor--- linear metadata,raid
(selected all LVs which are related to metadata of any type)
lvs -a -o name,vg_name,lv_attr,layout,type -S 'type={metadata,thin}'
LV VG Attr Layout Type
[pool_tmeta] vg ewi-aor--- level1,raid metadata,pool,thin
(selected all LVs which hold metadata related to thin)
lvs -a -o name,vg_name,lv_attr,layout,type -S 'type={thin,snapshot}'
LV VG Attr Layout Type
thin_snap1 vg Vwi---tz-k thin snapshot,thin
thin_snap2 vg Vwi---tz-k thin snapshot,thin
(selected all LVs which are thin snapshots)
lvs -a -o name,vg_name,lv_attr,layout,type -S 'layout=raid'
LV VG Attr Layout Type
[pool_tdata] vg rwi-aor--- level10,raid data,pool,thin
[pool_tmeta] vg ewi-aor--- level1,raid metadata,pool,thin
(selected all LVs with raid layout, any raid layout)
lvs -a -o name,vg_name,lv_attr,layout,type -S 'layout={raid,level1}'
LV VG Attr Layout Type
[pool_tmeta] vg ewi-aor--- level1,raid metadata,pool,thin
(selected all LVs with raid level1 layout exactly)
And so on...
Before the patch:
$ lvs -o name,active vg/lvol1 --driverloaded n
WARNING: Activation disabled. No device-mapper interaction will beattempted.
LV Active
lvol1 active
With this patch applied:
$ lvs -o name,active vg/lvol1 --driverloaded n
WARNING: Activation disabled. No device-mapper interaction will be attempted.
LV Active
lvol1 unknown
The same for active_{locally,remotely,exclusively} fields.
Also, rename headings for these fields (ActLocal/ActRemote/ActExcl).
Like other binary fields we already have:
$ lvs -o name,zero vg/lvx vg/pool vg/pool1
LV Zero
lvx unknown
pool
pool1 zero
$ lvs -o name,zero vg/lvx vg/pool vg/pool1 --binary
LV Zero
lvx -1
pool 0
pool1 1
lv_active_{locally,remotely,exclusively} display the original
"lv_active" field in a more separate way so that we can create
selection criteria in a binary-based form (yes/no).
The macros for reserved value definition makes the process a bit easier,
but there's still a place for improvement and make this even more
transparent. We can optimize and provide better automatism here later on.
Physical Volume Fields:
pv_allocatable - Whether this device can be used for allocation.
pv_exported - Whether this device is exported.
pv_missing - Whether this device is missing in system.
Volume Group Fields:
vg_permissions - VG permissions.
vg_extendable - Whether VG is extendable.
vg_exported - Whether VG is exported.
vg_partial - Whether VG is partial.
vg_allocation_policy - VG allocation policy.
vg_clustered - Whether VG is clustered.
Logical Volume Fields:
lv_volume_type - LV volume type.
lv_initial_image_sync - Whether mirror/RAID images underwent initial resynchronization.
lv_image_synced - Whether mirror/RAID image is synchronized.
lv_merging - Whether snapshot LV is being merged to origin.
lv_converting - Whether LV is being converted.
lv_allocation_policy - LV allocation policy.
lv_allocation_locked - Whether LV is locked against allocation changes.
lv_fixed_minor - Whether LV has fixed minor number assigned.
lv_merge_failed - Whether snapshot merge failed.
lv_snapshot_invalid - Whether snapshot LV is invalid.
lv_target_type - Kernel target type the LV is related to.
lv_health_status - LV health status.
lv_skip_activation - Whether LV is skipped on activation.
Logical Volume Info Fields
lv_permissions - LV permissions.
lv_suspended - Whether LV is suspended.
lv_live_table - Whether LV has live table present.
lv_inactive_table - Whether LV has inactive table present.
lv_device_open - Whether LV device is open.
The {pv,vg,lv,seg}_tags and lv_modules fields are reported as string
lists using the new dm_report_field_string_list - so we just pass
the list to the fn that takes care of reporting and item sorting itself.
This makes it easier to check against the fields (following patches for
report selection) and check whether size units are allowed or not
with the field value.
The common bits from lib/report/properties.[c|h] have
been moved to lib/properties/prop_common.[c|h] to allow
re-use of property handling functionality without
polluting the report handling functionality.
Signed-off-by: Tony Asleson <tasleson@redhat.com>
Add thin and thin pool lv creation support to lvm library
This is Mohan's thinp patch, re-worked to include suggestions
from Zdenek and Mohan.
V2: Remove const lvm_lv_params_create_thin
Add const lvm_lv_params_skip_zero_get
V3: Changed get/set to use generic functions like current
property
V4: Corrected macro in properties.c
V5: Fixed a bug in liblvm/lvm_lv.c function lvm_lv_create.
incorrectly used pool instead of lv_name when doing the
find_lv_in_vg call.
Based on work done by M. Mohan Kumar <mohan@in.ibm.com>
Signed-off-by: Tony Asleson <tasleson@redhat.com>
This patch adds the ability to set the minimum and maximum I/O rate for
sync operations in RAID LVs. The options are available for 'lvcreate' and
'lvchange' and are as follows:
--minrecoveryrate <Rate> [bBsSkKmMgG]
--maxrecoveryrate <Rate> [bBsSkKmMgG]
The rate is specified in size/sec/device. If a suffix is not given,
kiB/sec/device is assumed. Setting the rate to 0 removes the preference.
Add new lvs segment field 'Monitor' showing 3 states:
"monitored" - LV is monitored by dmeventd.
"not monitored" - LV is currently not being monitored by dmeventd
"" (empty) - LV does not support monitoring, or dmeventd support
is not compiled in.
'lvchange' is used to alter a RAID 1 logical volume's write-mostly and
write-behind characteristics. The '--writemostly' parameter takes a
PV as an argument with an optional trailing character to specify whether
to set ('y'), unset ('n'), or toggle ('t') the value. If no trailing
character is given, it will set the flag.
Synopsis:
lvchange [--writemostly <PV>:{t|y|n}] [--writebehind <count>] vg/lv
Example:
lvchange --writemostly /dev/sdb1:y --writebehind 512 vg/raid1_lv
The last character in the 'lv_attr' field is used to show whether a device
has the WriteMostly flag set. It is signified with a 'w'. If the device
has failed, the 'p'artial flag has priority.
Example ("nosync" raid1 with mismatch_cnt and writemostly):
[~]# lvs -a --segment vg
LV VG Attr #Str Type SSize
raid1 vg Rwi---r-m 2 raid1 500.00m
[raid1_rimage_0] vg Iwi---r-- 1 linear 500.00m
[raid1_rimage_1] vg Iwi---r-w 1 linear 500.00m
[raid1_rmeta_0] vg ewi---r-- 1 linear 4.00m
[raid1_rmeta_1] vg ewi---r-- 1 linear 4.00m
Example (raid1 with mismatch_cnt, writemostly - but failed drive):
[~]# lvs -a --segment vg
LV VG Attr #Str Type SSize
raid1 vg rwi---r-p 2 raid1 500.00m
[raid1_rimage_0] vg Iwi---r-- 1 linear 500.00m
[raid1_rimage_1] vg Iwi---r-p 1 linear 500.00m
[raid1_rmeta_0] vg ewi---r-- 1 linear 4.00m
[raid1_rmeta_1] vg ewi---r-p 1 linear 4.00m
A new reportable field has been added for writebehind as well. If
write-behind has not been set or the LV is not RAID1, the field will
be blank.
Example (writebehind is set):
[~]# lvs -a -o name,attr,writebehind vg
LV Attr WBehind
lv rwi-a-r-- 512
[lv_rimage_0] iwi-aor-w
[lv_rimage_1] iwi-aor--
[lv_rmeta_0] ewi-aor--
[lv_rmeta_1] ewi-aor--
Example (writebehind is not set):
[~]# lvs -a -o name,attr,writebehind vg
LV Attr WBehind
lv rwi-a-r--
[lv_rimage_0] iwi-aor-w
[lv_rimage_1] iwi-aor--
[lv_rmeta_0] ewi-aor--
[lv_rmeta_1] ewi-aor--
New options to 'lvchange' allow users to scrub their RAID LVs.
Synopsis:
lvchange --syncaction {check|repair} vg/raid_lv
RAID scrubbing is the process of reading all the data and parity blocks in
an array and checking to see whether they are coherent. 'lvchange' can
now initaite the two scrubbing operations: "check" and "repair". "check"
will go over the array and recored the number of discrepancies but not
repair them. "repair" will correct the discrepancies as it finds them.
'lvchange --syncaction repair vg/raid_lv' is not to be confused with
'lvconvert --repair vg/raid_lv'. The former initiates a background
synchronization operation on the array, while the latter is designed to
repair/replace failed devices in a mirror or RAID logical volume.
Additional reporting has been added for 'lvs' to support the new
operations. Two new printable fields (which are not printed by
default) have been added: "syncaction" and "mismatches". These
can be accessed using the '-o' option to 'lvs', like:
lvs -o +syncaction,mismatches vg/lv
"syncaction" will print the current synchronization operation that the
RAID volume is performing. It can be one of the following:
- idle: All sync operations complete (doing nothing)
- resync: Initializing an array or recovering after a machine failure
- recover: Replacing a device in the array
- check: Looking for array inconsistencies
- repair: Looking for and repairing inconsistencies
The "mismatches" field with print the number of descrepancies found during
a check or repair operation.
The 'Cpy%Sync' field already available to 'lvs' will print the progress
of any of the above syncactions, including check and repair.
Finally, the lv_attr field has changed to accomadate the scrubbing operations
as well. The role of the 'p'artial character in the lv_attr report field
as expanded. "Partial" is really an indicator for the health of a
logical volume and it makes sense to extend this include other health
indicators as well, specifically:
'm'ismatches: Indicates that there are discrepancies in a RAID
LV. This character is shown after a scrubbing
operation has detected that portions of the RAID
are not coherent.
'r'efresh : Indicates that a device in a RAID array has suffered
a failure and the kernel regards it as failed -
even though LVM can read the device label and
considers the device to be ok. The LV should be
'r'efreshed to notify the kernel that the device is
now available, or the device should be 'r'eplaced
if it is suspected of failing.
There are new reporting fields for Embedding Area: ea_start and ea_size.
An example of 1m Embedding Area and relevant reporting fields:
raw/~ # pvs -o pv_name,pe_start,ea_start,ea_size
PV 1st PE EA start EA size
/dev/sda 2.00m 1.00m 1.00m
The heading 'Copy%' is specific to PVMOVE volumes, but can be generalized
to apply to LVM mirrors also. It is a bit awkward to use 'Copy%' for
RAID 4/5/6, however - 'Sync%' would be more appropriate. This is why
RAID 4/5/6 have not displayed their sync status by any means available to
'lvs' yet.
Example (old):
[root@hayes-02 lvm2]# lvs vg
LV VG Attr LSize Pool Origin Data% Move Log Cpy%Sy Convert
lv vg -wi-a---- 1.00g
raid1 vg rwi-a-r-- 1.00g 100.00
raid4 vg rwi-a-r-- 1.01g
raid5 vg rwi-a-r-- 1.01g
raid6 vg rwi-a-r-- 1.01g
This patch changes the heading to 'Cpy%Sync' and allows RAID 4/5/6 to print
their sync percent in this field.
Example (new):
[root@hayes-02 lvm2]# lvs vg
LV VG Attr LSize Pool Origin Data% Move Log Cpy%Sync Convert
lv vg -wi-a---- 1.00g
raid1 vg rwi-a-r-- 1.00g 100.00
raid4 vg rwi-a-r-- 1.01g 100.00
raid5 vg rwi-a-r-- 1.01g 100.00
raid6 vg rwi-a-r-- 1.01g 100.00
I think it's better not to abbreviate human-readable fields like
'discard' to a single character. Users can truncate it to the
first character themselves if they wish.
It's confusing to use the variable name discard for different things in
different places - use discard_str when it's a string not the enum.
New field Data% is able to display info about
thin_pool, thin, snapshot and has generic meaning here.
Simple Time/Host field are here to display host and time creation.
A gentle reminder that anyone relying on the output of reporting commands
like lvs in scripts must use -o to guarantee they get the fields they expect.
The default sequence of fields can change from release to release.
Equally, the 'attr' fields can have new values introduced and/or characters
appended to them.
Similar to 'get' property internal functions.
Add specific 'set' function for vg_mda_copies.
Signed-off-by: Dave Wysochanski <wysochanski@pobox.com>
Reviewed-by: Petr Rockai <prockai@redhat.com>
Move the creating of the 'attr' strings into a common function so
they can be called from the 'disp' functions as well as the new
'get' property functions.
Add "_dup" suffix to indicate memory is allocated.
Refactor pvstatus_disp to take pv argument and call pv_attr_dup().
The 'id' entries in columns.h are the report field names. Since these are
unique, we'd like to use them in generation of 'get' / 'set' functions.
As a step towards using them for this purpose, remove the explicit double
quotes and use the macro '#' character to add the double quotes back when
placing them into the '_fields' array 'id' member.
Add a 'flags' field to columns.h, and set it to 0 by default.
Define FIELD_MODIFIABLE flag to indicate whether a 'set' function exists
to change the field's value.
Define a new pvs field, pv_mda_used_count, and a new vgs field,
vg_mda_used_count to match the existing pv_mda_count and vg_mda_count.
These new fields count the number of mdas that have the 'ignored' bit
clear (they are in use on the PV / VG). Also define various supporting
functions to implement the counting as well as setting the ignored
flag and determining if an mda is ignored. These high level functions
call into the lower level location independent mda ignore functions
defined by earlier patches.
Note that counting ignored mdas in a vg requires traversing both lists
and checking for the ignored bit on the mda. The count of 'ignored'
mdas then is defined by having the bit set, not by which list the mda
is on. The list does determine whether LVM actually does read/write to
the mda, though we must count the bits in order to return accurate numbers
for the various counts. Also, pv_mda_set_ignored must search both vg
lists for ignored mda. If the state changes and needs to be committed
to disk, the ignored mda will be on the non-ignored list.
Note also in pv_mda_set_ignored(), we must properly manage the mda lists.
If we change the ignored state of an mda, we must change any mdas on
vg->fid->metadata_areas that correspond to this pv. Also, we may
need to allocate a copy of the mda, as is done when fid->metadata_areas
is populated from _vg_read(), if we are un-ignoring an ignored mda.
Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Add lvs origin_size field.
Fix linux configure --enable-debug to exclude -O2.
Still a few rough edges, but hopefully usable now:
lvcreate -s vg1 -L 100M --virtualoriginsize 1T
# pvs -a -o devices
Volume group name (null) has invalid characters
Skipping volume group (null)
...
_pvsegs_sub_single creates fake vg, we need to check
that pv is real here.
When reporting explicitly label attributes (pv_uuid for example), we do not
need to read metadata.
This patch separate the label fileds and removes scan_vgs_for_pvs
in process_each_pv() if not needed.
(There should be no user visible change in output.)
Reports the size of the smallest metadata area in a PV or a VG.
Useful to confirm pvcreate --metadatasize or pvmetadatasize setting in
/etc/lvm/lvm.conf file.
NOTE: Actual value in these fields will most always differ from that
given in pvcreate options due to rounding and alignment effects.
